linux-kernel - [PATCH printk v8 33/35] panic: Mark emergency section in oops

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Message-Id: <20240820063001.36405-34-john.ogness@linutronix.de>
Date: Tue, 20 Aug 2024 08:35:59 +0206
From: John Ogness <john.ogness@...utronix.de>
To: Petr Mladek <pmladek@...e.com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jani Nikula <jani.nikula@...el.com>,
	Baoquan He <bhe@...hat.com>,
	Joel Granados <j.granados@...sung.com>,
	Feng Tang <feng.tang@...el.com>,
	Uros Bizjak <ubizjak@...il.com>
Subject: [PATCH printk v8 33/35] panic: Mark emergency section in oops

Mark an emergency section beginning with oops_enter() until the
end of oops_exit(). In this section, every printk() call will
attempt to directly flush to the consoles using the EMERGENCY
priority.

The very end of oops_exit() performs a kmsg_dump(). This is not
included in the emergency section because it is another
flushing mechanism that should occur after the consoles have
flushed the oops messages.

Signed-off-by: John Ogness <john.ogness@...utronix.de>
Reviewed-by: Petr Mladek <pmladek@...e.com>
---
 kernel/panic.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/panic.c b/kernel/panic.c
index 1a10b6e2a855..753d12f4dc8f 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -685,6 +685,7 @@ bool oops_may_print(void)
  */
 void oops_enter(void)
 {
+	nbcon_cpu_emergency_enter();
 	tracing_off();
 	/* can't trust the integrity of the kernel anymore: */
 	debug_locks_off();
@@ -707,6 +708,7 @@ void oops_exit(void)
 {
 	do_oops_enter_exit();
 	print_oops_end_marker();
+	nbcon_cpu_emergency_exit();
 	kmsg_dump(KMSG_DUMP_OOPS);
 }
 
-- 
2.39.2